Effects of Ionizing Radiation on Neural Precursor Cells (IN8-1.008)

Abstract

Objective: To elucidate cellular and molecular changes associated with the exposure of neural stem cells (NSCs) to high and low doses of ionizing radiation. Background Damage to normal human brain cells from targeted exposure to ionizing radiation may occur during the course of cancer radiotherapy or from accidental exposure. Delayed effects may complicate the acute immediate effects, and in particular have been associated with neurodegeneration and cognitive decline. These delayed effects may arise from the slow death of irradiated cells, damage to cells that survive the radiation exposure, or from negative effects on normal cell replenishment of non-targeted brain cells from neural stem cells. Design/Methods: Subventricular zone (SVZ) neural precursors isolated from newborn mouse pups were analyzed for survival, proliferation and differentiation after exposure to low and high doses of γ rays (range from 0 to 8 Gy). Results: The ability of the neurospheres to differentiate into astroglia, neurons, and oligodendroglia was assessed in the studied groups 8 days after irradiation. There were no significant changes in the neurosphere differentiation ability between the irradiated cells and controls (p>0.05). Surprisingly, the number of neurospheres formed showed no significant change from control, up to 8 Gy of γ irradiation. Meanwhile, the size of the spheres increased slightly at low doses without any significant change(0.4 or 0.5 Gy), and decreased dramatically at 8 Gy (p Conclusions: Our data suggest that neural stem cells/neural precursors derived from the SVZ are resistant to ionizing irradiation. However, their proliferation is inhibited subsequent to exposure to ionizing radiation. Supported by: Start up fund. Disclosure: Dr. Chen has nothing to disclose. Dr. Levison has nothing to disclose. Dr. De Toledo has nothing to disclose. Dr. Azzam has nothing to disclose. Dr. Souayah has received personal compensation for activities with Walgreens as a consultant. Dr. Souayah has received research support from Talecris.